In my companion application, Ser. No. 055,373 filed July 6, 1979, there is disclosed an in-hole fluid motor drilling apparatus, wherein the rotor of the motor is connected to one end of the shaft which is supported in the bearing housing and has a bit at its other end. Drilling weight is transferred from the housing to the shaft, and thence to the bit during drilling operations. A clutch is provided between the housing and the shaft which can be engaged without increasing the load on the bit. While such clutches can be engaged by relative motion of the housing and the shaft, without increasing the load on the bit, as disclosed in my companion applications Ser. Nos. 067,882 filed Aug. 20, 1979 and 068,147, filed Aug. 20, 1979, by longitudinal upward movement of the housing with respect to the stuck bit, or by rotation of the housing relative to the stuck bit, the clutches in my pending application, Ser. No. 55,373, are disengaged by fluid pressure and engaged by a spring when the circulation of drilling and motor fluid is reduced. Specifically, the clutches of the above-identified application (Ser. No. 55,373) are disengaged by the differential pressure caused by the flow of fluid through a restriction in the bearing assembly, which is of the mud lubricated type.
Sealed bearings are also known for use with in-hole fluid driven motors. One example of a sealed bearing assembly is that illustrated in Tschirky et al, U.S. Pat. No. 4,098,561, granted July 4, 1978. Another sealed bearing assembly for in-hole motors is disclosed in the pending application filed by me and John E. Tschirky on July 25, 1977, Ser. No. 818,423.
In the case of in-hole motor drill assemblies of the fluid driven types, wherein the rotary drill bit is driven by the in-hole motor disposed between the running pipe string and the bit, it is not, as a rule, possible to cause the bit to rotate by rotation of the running or drill pipe string above the motor. The reaction torque of such in-hole motors is, generally, taken by a rotary table at the surface of the bore hole, whereby the drill pipe string can either be held stationery, or if desired, rotated, while the motor is driving the bit, to obviate the wedging of the pipe string. However, if the bit becomes stuck in the bore hole, such in-hole motors will stall and the rotation of the bit may not be possible, notwithstanding the availability of additional drilling fluid pressure. When such motor drills are stalled in the bore hole rotation of the drill pipe string by the rotary table, is ineffective to cause bit rotation, since there is no positive drive between the stator and the rotor, and the bit remains wedged or stuck in the hole. The bit clutch of Trzeciak provides a structure enabling rotation of the bit by rotation of the drill string without interfering with normal operation of the drilling apparatus.